Expected effects of the use of the Oosterschelde storm surge barrier on the survival of the intertidal fauna: Part 1—The effects of prolonged emersion

In order to assess limits for the use of the Oosterschelde storm surge barrier (SW Netherlands) within which damage to the environment will be minimal, effects of prolonged emersion from 2 to 8 days on survival of the intertidal fauna were investigated in semi-field and laboratory experiments. It was found that during most of the year a period of prolonged emersion of 2 days will only cause mortality in a few species, providing extremely low or high temperatures do not occur. Longer periods of emersion, however, will cause a high mortality among many species, especially small polychaetes and anemones, in most seasons except winter and early spring. It is discussed, that the differences in sensitivity between species may be due to differences in size/volume ratios or possession of a shell, protecting the animal from desiccation. The higher sensitivity in summer may, in some species, coincide with the reproductive cycle.